?Classical? and ?non-classical? reproductive steroids in fish

Kime, David E.

doi:10.1007/bf00045230

Cited by 293 publications

(195 citation statements)

References 95 publications

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“…parvicornis. The most active androgens in fishes are 11-oxo-4-androstens (Borg, 1994) with 11-ketoandrostenedione, 11␤-hydroxyandrostenedione, and 11␤-hydroxytestosterone as alternative candidates to KT in some teleosts, where they appear to be the most active androgens stimulating SSC and reproductive behaviors (see reviews by Kime, 1993;Borg, 1994). This possibility will require determining whether these steroids (if any) are present in P.s.…”

Section: Differential Role Of Mt and Kt On The Activation Of Bourgeoimentioning

confidence: 99%

Effects of Androgens on Social Behavior and Morphology of Alternative Reproductive Males of the Azorean Rock-Pool Blenny

Oliveira

Carneiro

Canário

et al. 2001

Hormones and Behavior

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In the Azorean rock-pool blenny Parablennius sanguinolentus parvicornis two sequential reproductive tactics occur. Larger and older males establish breeding territories, while some of the smaller males become attached to nest-holder territories, acting as satellites on these territories, which they help to defend while trying parasitic fertilizations when females go in the nests to spawn. In the present paper we tested the effects of the androgens 17␣-methyltestosterone (MT) and 11-ketotestosterone (KT) in the expression of male secondary sex characters and bourgeois behavior in satellite males. One week after satellites were implanted with Silastic tubes containing MT, KT, or castor oil (control), androgen-treated satellites had developed male secondary sex traits such as longer and wider male-type genital papilla and anal glands that secrete a sex pheromone, both traits being less expressed or absent, respectively, in satellite males. Androgen treatment had no effect on the gonadosomatic index or on the development of the testicular gland. KT treatment had a positive effect on relative liver weight. In terms of behavior, androgen-implanted individuals were less aggressive both in a mirror test and toward females when these were introduced into their tanks. MT-treated individuals spend more time inside the provided nests. Only androgen-implanted satellites managed to have the females entering their nests. When given a chance in a group tank either to try to attract females to their own nest or to act as satellites of an already established nest-holder's nest, MT-implanted males spent significantly more time in their own nest than near the nest-holder nest. These data suggest that androgens, particularly testosterone, may be involved in mating tactic switching in this species.

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Section: Differential Role Of Mt and Kt On The Activation Of Bourgeoimentioning

confidence: 99%

Effects of Androgens on Social Behavior and Morphology of Alternative Reproductive Males of the Azorean Rock-Pool Blenny

Oliveira

Carneiro

Canário

et al. 2001

Hormones and Behavior

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“…The expression of SSC is known to be related to the circulating levels of androgens (Borg, 1994;Liley and Stacey, 1983;Oliveira et al, 2001b). In teleost fish testosterone (T) and 11-ketotestosterone (11KT) are the major androgens that regulate the expression of SSC (Kime, 1993) and also the expression of reproductive behavior (Oliveira and Gonçalves, 2008). In species with alternative reproductive tactics (ART), males that follow a conventional tactic, investing resources in mate acquisition and monopolization ('bourgeois' males sensu Taborsky, 1997), have generally higher circulating levels of 11KT than those of parasitic males (sensu Taborsky, 1997) that exploit this investment using an alternative tactic, whereas T shows no clear pattern (Brantley et al, 1993b;Oliveira, 2006).…”

Section: Introductionmentioning

confidence: 99%

Environmental modulation of androgen levels and secondary sex characters in two populations of the peacock blenny Salaria pavo

Saraiva

Gonçalves

Oliveira

2010

Hormones and Behavior

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Morphology and endocrinology were studied in two populations of the peacock blenny Salaria pavo, with different regimes of sexual selection imposed by differences in nest site availability. The peacock blenny is a small, sexually dimorphic benthic fish that presents exclusive paternal care of the clutch and inhabits rocky shores of the Mediterranean and adjacent Atlantic areas. In a population from the Gulf of Trieste (Northern Adriatic sea) inhabiting rocky shores where nest sites are abundant, male-male competition for nests is low, males court females and a low frequency of alternative reproductive tactics (small, parasitic femalemimicking sneaker males that change tactic into nest holders in subsequent breeding seasons) occurs. Conversely at Ria Formosa, a coastal lagoon in Southern Portugal, where nest sites are scarce and highly aggregated, male-male competition for nests is very high, there is sex-role reversal with female courtship and a high frequency of alternative reproductive tactics is observed. Concomitantly, at Ria Formosa nest holder males are larger and present more developed secondary sex characters and higher levels of 11KT than at the Gulf of Trieste. However, the gonads of nest holders and parasitic males were larger in the Gulf of Trieste population. Competition for nests at Ria Formosa seems to promote more developed secondary sex characters in nest site scarcity conditions, while competition for females at the Gulf of Trieste seems to be spurring sperm competition among males in populations where nest sites are more abundant. 11KT was thus associated with the development and expression of secondary sex characters in contrasting environments. These results exemplify how the modulation of behavioral plasticity and secondary sex characters by the social environment can be mediated by androgens.

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“…The values reject the hypothesis that spawning rate is associated with 'brood size' only ( Fig. 1, scenario the androgen 11-KT because this is the major biologically active androgen in male teleosts (Kime 1993;Borg 1994 Rodgers et al 2006). The lack of a negative relationship between 11-KT and parental care might be explained by the fact that male competitive behaviours and parental care are not mutually exclusive in fish.…”

Section: Androgen Levels and Variation In Brood Sizementioning

confidence: 78%

Adjustment of brood size and androgen levels in a teleost species with exclusive male parental care

2009

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Blenniidae brood size manipulation intersexual selection male quality peacock blenny Salaria pavo testosterone In maximizing reproductive success, individuals face a trade-off between parental care for their current offspring and investing in androgen-dependent sexual traits to produce further offspring. It has thus been proposed that parental effort would suppress androgen levels. Here, we studied parental effort by manipulating brood size in the peacock blenny, Salaria pavo, a littoral fish species in which males show long periods of paternal care. We focused on the effects of brood size on female spawning rate (measured as number of eggs received in the nest by focal males) and androgen levels. We found a positive linear relationship between brood size and the number of eggs received subsequently. Accordingly, spawning rate increased for males with experimentally enlarged broods while it decreased for males in which brood size was reduced. However, over a longer time interval, brood sizes of both treatments returned to the nonmanipulated brood size, suggesting an effect of additional factors such as male quality. Brood size did not show the expected negative relationship with levels of testosterone and 11-ketotestosterone. On the contrary, testosterone levels were positively correlated with brood size. However, in agreement with the prediction, changes in the level of parental care by manipulation of brood size showed an inverse relationship with testosterone levels. As with brood size, given time, testosterone levels tended to return to nonmanipulated levels. Such changes suggest that males adjust their brood size to an individual value through androgen modulation of courtship or other traits influencing female spawning rate. Ó

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?Classical? and ?non-classical? reproductive steroids in fish

Cited by 293 publications

References 95 publications

Effects of Androgens on Social Behavior and Morphology of Alternative Reproductive Males of the Azorean Rock-Pool Blenny

Effects of Androgens on Social Behavior and Morphology of Alternative Reproductive Males of the Azorean Rock-Pool Blenny

Environmental modulation of androgen levels and secondary sex characters in two populations of the peacock blenny Salaria pavo

Adjustment of brood size and androgen levels in a teleost species with exclusive male parental care

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